This application is in response to RFA 88-CA-2, National Collaborative Imaging Trials project. We are requesting to join the ongoing group of institutions, Radiologic Diagnostic Oncology Group (RDOG) and participate in evaluation of the comparative merits of imaging modalities in staging and followup of patients with pancreatic and colorectal carcinoma. Our joining in the collaborative group will assure that the comparisons of newer diagnostic imaging modalities can be instituted in a timely fashion and data can be analyzed in a controlled manner. We intend to utilize the facilities of the Operation Center and Statistical and Data Management group as established by the ACR in response to RFA 86-CA-10. Our joining with this group will ensure that we can 1) optimize image quality as has been done at previously funded participating sites; 2) obtain consistent and complete data at our own site comparable to data with already participating sites; 3) add to the established film library to allow derivative studies in subsequent year; 4) and participate in collaborative imaging data analyses of clinical efficacy and help develop potential algorithms which will ultimately make maximal use of the information available from these examinations. This will be achieved by utilizing "state-of-the-art" equipment, generating Receiver Operating Characteristic Curve (ROC) analyses incorporating appropriate bias corrections to generate meaningful data in large numbers of patients. The application addresses the utilization of radiologic imaging in staging of pancreatic and colorectal cancer. The absolute value of Computed Tomography (CT), Magnetic Resonance Imaging (MRI) in patients with carcinoma of the pancreas will be determined; the accuracy in preoperative staging of both techniques will be assessed. For staging colon carcinoma we will examine the accuracy of CT and MRI in both local staging and detection of distant metastases. For rectal carcinoma we will additionally evaluate the role of transrectal sonography as well as CT and MRI in evaluating the initial staging, the depth of penetration of the tumor, as well as the extent of distant disease. In both protocols, timely followup studies will also be obtained to evaluate the roles of these modalities in monitoring followup in these patients.